Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 32
Filtrar
1.
Sensors (Basel) ; 23(17)2023 Aug 27.
Artículo en Inglés | MEDLINE | ID: mdl-37687910

RESUMEN

Wearable assistant devices play an important role in daily life for people with disabilities. Those who have hearing impairments may face dangers while walking or driving on the road. The major danger is their inability to hear warning sounds from cars or ambulances. Thus, the aim of this study is to develop a wearable assistant device with edge computing, allowing the hearing impaired to recognize the warning sounds from vehicles on the road. An EfficientNet-based, fuzzy rank-based ensemble model was proposed to classify seven audio sounds, and it was embedded in an Arduino Nano 33 BLE Sense development board. The audio files were obtained from the CREMA-D dataset and the Large-Scale Audio dataset of emergency vehicle sirens on the road, with a total number of 8756 files. The seven audio sounds included four vocalizations and three sirens. The audio signal was converted into a spectrogram by using the short-time Fourier transform for feature extraction. When one of the three sirens was detected, the wearable assistant device presented alarms by vibrating and displaying messages on the OLED panel. The performances of the EfficientNet-based, fuzzy rank-based ensemble model in offline computing achieved an accuracy of 97.1%, precision of 97.79%, sensitivity of 96.8%, and specificity of 97.04%. In edge computing, the results comprised an accuracy of 95.2%, precision of 93.2%, sensitivity of 95.3%, and specificity of 95.1%. Thus, the proposed wearable assistant device has the potential benefit of helping the hearing impaired to avoid traffic accidents.


Asunto(s)
Pérdida Auditiva , Dispositivos Electrónicos Vestibles , Humanos , Ambulancias , Audición , Accidentes de Tránsito
2.
Small ; 18(39): e2106127, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-36026566

RESUMEN

Thin film catalysts, giving a different morphology, provide a significant advantage over catalyst particles for the gas evolution reaction. Taking the advantages of sputter deposition, a high entropy alloy (HEA) thin film electrocatalyst is hereby reported for the oxygen evolution reaction (OER). The catalyst characteristics are investigated not only in its as-deposited state, but also during and after the OER. For comparison, unary, binary, ternary, and quaternary thin film catalysts are prepared and characterized. The surface electronic structure modification due to the addition of a metal is studied experimentally and theoretically using density functional theory calculation. It is demonstrated that sputtered FeNiMoCrAl HEA thin film exhibits OER performance superior to all the reported HEA catalysts with robust electrocatalytic activity having a low overpotential of 220 mV at 10 mA cm-2 , and excellent electrochemical stability at different constant current densities of 10 and 100 mA cm-2 for 50 h. Furthermore, the microstructure transformation is investigated during the OER, which is important for the understanding of the OER mechanism provided by HEA electrocatalyst. Such a finding will contribute to future catalyst design.

3.
Biosens Bioelectron ; 211: 114339, 2022 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-35588636

RESUMEN

By D-arginine and L-arginine chiral peptides induced spin selectivity and Au NPs enhanced spin polarization, chiral peptides purification has been effectively simplified and the purification performance has raised from a mixture system. The angular momentums of light are operated by the polarizer and wave plates. Au NPs decorated ZnO nanorods electrodes are utilized to modulate the polarization of spintronic. Seed growth methods are for synthesizing spherical Au NPs. UV light reduction methods are for urchin-liked Au NPs. Au NPs are decorated on ZnO nanorods electrodes for rising photon to electron conversion efficiency and enhancing spin polarization rates by surface plasmon effect. From our results, photon to the electron conversion efficiency of ZnO nanorods electrodes has effectively enhanced by urchin-liked Au NPs decorating. Ultrahigh localized plasmon conversion efficiency as high as 60% was also obtained. Besides, density functional theory (DFT) calculations simulated the force on spintronic. Since the D-arginine and L-arginine are on Au substrate, DFT results demonstrate different angular momentum and spin polarization coupling. Along with urchin-liked Au NPs rising chiral induced spin polarization by surface plasmon resonance, the sensitivity of chiral arginine has been raised around 5000% from bare ZnO nanorods electrodes. The purification and separation time of a specific chiral arginine only needs 5 min.


Asunto(s)
Técnicas Biosensibles , Óxido de Zinc , Arginina , Oro , Péptidos
4.
Neurol Ther ; 10(2): 1015-1028, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34515952

RESUMEN

INTRODUCTION: Concentrations of plasma biomarkers associated with Alzheimer's disease have been reported to be as low as several tens of picograms/milliliter (pg/ml). However, in assays measuring these biomarkers, it is likely that repeated measurements are necessary to obtain reliable values. METHODS: We performed assays as a single test or as duplicate, quadruplicate, fivefold and tenfold repeated tests, on samples spiked with different concentrations of amyloid ß 1-40 (Aß1-40; 1-1000 pg/ml), Aß1-42 (1-30,000 pg/ml) and total Tau protein (T-Tau; 0.1-1000 pg/ml), with the aim to to calculate the coefficients of variation (CVs). RESULTS: The results demonstrated common changes in the CVs with changes in the number of tests for a given sample: the CVs decreased with increases in the number of tests from one to ten. All CV values were distributed within the range of 0.35 to 15.5%; as such, the CV values were all lower than the acceptable value of 20%. CONCLUSION: Based on this study, a single assay of Aß1-40, Aß1-42 and T-Tau, respectively, provides reliable results in terms of the measurement of that plasma biomarker.

5.
J Clin Med ; 10(12)2021 Jun 16.
Artículo en Inglés | MEDLINE | ID: mdl-34208437

RESUMEN

Pyogenic liver abscess (PLA) is a major life-threatening disease with varied clinical features. This study aimed to determine predictors of mortality in patients with PLA using criteria determined upon admission. We retrospectively examined the data of 324 hospitalized adults in whom liver abscesses were confirmed using abdominal ultrasound and/or computed tomography. The relationship between various risk factors was assessed using multivariate analysis. A total of 109 (33.6%) patients were admitted to the intensive care unit (ICU). The overall mortality rate was 7.4% and was higher among ICU patients than non-ICU patients (21.1% vs. 0.5%, p < 0.001). PLA patients with an Acute Physiology and Chronic Health Evaluation (APACHE) II score ≥18 had a 19.31-fold increased risk, and those with concomitant infections had a 34.33-fold increased risk of 30-day mortality according to multivariate analysis. The estimated area under the receiver operating characteristic curve for predicting 30-day mortality revealed that APACHE II score ≥18 (sensitivity of 75% and specificity of 84%, p < 0.0001) had better discriminative power than Sequential Organ Failure Assessment (SOFA) ≥6 (sensitivity of 81% and specificity of 66%, p < 0.0001). APACHE II has shown better discrimination ability than SOFA in predicting mortality in PLA patients. To improve outcomes in patients with PLA, future management strategies should focus on high-risk patients.

6.
Adv Sci (Weinh) ; 8(6): 2002446, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33747721

RESUMEN

Herein, a new high entropy material is reported, i.e., a noble metal-free high entropy glycerate (HEG), synthesized via a simple solvothermal process. The HEG consists of 5 different metals of Fe, Ni, Co, Cr, and Mn. The unique glycerate structure exhibits an excellent oxygen evolution reaction (OER) activity with a low overpotential of 229 and 278 mV at current densities of 10 and 100 mA cm-2, respectively, in 1 m KOH electrolyte, outperforming its subsystems of binary-, ternary-, and quaternary-metal glycerates. The HEG also shows outstanding stability and durability in the alkaline electrolyte. The result demonstrates the significance of synergistic effect that gives additional freedoms to modify the electronic structure and coordination environment. Moreover, HEG@HEG electrolyzer shows a good overall water splitting performance and durability, requiring a cell voltage of 1.63 V to achieve a current density of 10 mA cm-2.

7.
Nanotechnology ; 32(15): 155704, 2021 Apr 09.
Artículo en Inglés | MEDLINE | ID: mdl-33373982

RESUMEN

The magnetotransport properties of a hybrid InSe/monolayer graphene in a SiC system are systematically studied. Compared to those of its bare graphene counterpart, in InSe/graphene, we can effectively modify the carrier density, mobility, effective mass, and electron-electron (e-e) interactions enhanced by weak disorder. We show that in bare graphene and hybrid InSe/graphene systems, the logarithmic temperature (lnT) dependence of the Hall slope R H = Î´R xy /δB = Î´ρ xy /δB can be used to probe e-e interaction effects at various temperatures even when the measured resistivity does not show a lnT dependence due to strong electron-phonon scattering. Nevertheless, one needs to be certain that the change of R H is not caused by an increase of the carrier density by checking the magnetic field position of the longitudinal resistivity minimum at different temperatures. Given the current challenges in gating graphene on SiC with a suitable dielectric layer, our results suggest that capping a van der Waals material on graphene is an effective way to modify the electronic properties of monolayer graphene on SiC.

8.
Medicine (Baltimore) ; 97(45): e13201, 2018 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-30407359

RESUMEN

Human papillomavirus (HPV) infection is associated with cancer and can be prevented through vaccination. Few studies from Taiwan have reported on HPV infection among human immunodeficiency virus (HIV)-infected subjects. The aim of this study was to examine the prevalence of HPV infection among men who have sex with men (MSM) with and without HIV infection in Taiwan, and explore the behavioral risk factors thereof.We conducted a cross-sectional study in Taiwan during 2013 to 2016 to collect data on MSM aged 20 years or older. We used a questionnaire in a face-to-face interview, and subsequently collected oral, anal, and genital specimens from HIV-infected and HIV-uninfected subjects. Multivariate analysis was performed to predict factors associated with high-risk HPV (HR-HPV) positivity.Overall, 279 subjects, including 166 (59.5%) HIV-uninfected and 113 (40.5%) HIV-infected men were enrolled. Compared to HPV-negative subjects, HPV-positive subjects had significantly higher rates of receptive anal sex (91.3% vs 75.6%), substance use (22.6% vs 11%), history of sexually transmitted infections (75.7% vs 38.4%), anogenital or oral warts (39.1% vs 6.72%), syphilis (32.2% vs 11.6%), and HIV infection (69.6% vs 20.1%). We detected 489 HPV deoxyribonucleic acid (DNA) types (through 379 viable specimens), of which 43.6%, 5.7%, 56.4%, and 10.4% were HR-HPV type, HPV type 16, low-risk HPV types, and HPV type 6, respectively. In multivariate analysis, HIV-infected subjects had a significantly higher prevalence of HR-HPV infection (adjusted odds ratio, 5.80; 95% confidence interval, 2.57-13.11), compared to HIV-uninfected subjects.These results suggest that the prevalence of HPV infection was high among HIV-infected MSM. Additionally, anal HPV infection was observed to be common among both HIV-infected and HIV-uninfected MSM in Taiwan. The prevalence of oral and genital HPV infection, HR-HPV DNA types, and multiple HPV types was higher in HIV-infected subjects than in HIV-uninfected subjects. As only 35% of subjects practiced safe sex, we recommend routine HPV vaccination with 4-valent HPV or 9-valent HPV vaccines for both MSM, and HIV-infected subjects.


Asunto(s)
Infecciones por VIH/complicaciones , Homosexualidad Masculina/estadística & datos numéricos , Papillomaviridae/genética , Infecciones por Papillomavirus/epidemiología , Adulto , Canal Anal/virología , Recuento de Linfocito CD4 , Estudios Transversales , Genitales Masculinos/virología , Conductas de Riesgo para la Salud , Humanos , Masculino , Persona de Mediana Edad , Infecciones por Papillomavirus/complicaciones , Prevalencia , Factores de Riesgo , Encuestas y Cuestionarios , Taiwán/epidemiología , Carga Viral , Adulto Joven
9.
Hu Li Za Zhi ; 65(2): 54-63, 2018 Apr.
Artículo en Chino | MEDLINE | ID: mdl-29564857

RESUMEN

BACKGROUND: There has been a global consensus since 2016 that antiretroviral therapy (ART) should be initiated following HIV diagnosis regardless of CD4-count test results. Identifying an instrument that is able to accurately assess the readiness of HIV-infected persons for treatment initiation is thus critical. PURPOSE: (1) To evaluate the comparative readiness of patients receiving ART and those who are not yet on ART; (2) to evaluate the respective readiness variation within these 2 groups over a one-year period; and (3) to identify the cutoff value for medication readiness that indicates the ideal time to initiate ART. METHODS: A multicenter cohort study design was conducted and 297 newly diagnosed patients with HIV were enrolled at four time points, including: baseline and at 1, 3-6, and 9-12 months after ART initiation. Data collection included a demographics datasheet, the Chinese version of the HIV Medication Readiness Scale (HMRS), and 2 items, readiness to take ART for a long period of time and confidence in adhering to ART, which were scored using a 10-point Likert scale. RESULTS: Overall, 224 (75.4%) of the participants had initiated ART. Over time, the medication readiness of participants with ART initiation had increased significantly over that of non-ART user (p < .001). The mean scores of the 2-item self-rated readiness scale for patients with ART initiation were significantly greater than those without (p < .001). The cutoff values for HMRS, self-rating readiness for ART, and confidence in adherence to ART were 23.5, 5.5, and 6.5, respectively. CONCLUSIONS / IMPLICATIONS FOR PRACTICE: The optimal cutoff value of the Chinese version HMRS for evaluating HAART initiation among persons with HIV infection was 23.5. HIV healthcare professionals may apply the Chinese version HMRS and the two simple self-rated items as a clinical tool for quickly assessing the initiation of ART in people living with HIV.


Asunto(s)
Fármacos Anti-VIH/uso terapéutico , Infecciones por VIH/tratamiento farmacológico , Adulto , Anciano , Estudios de Cohortes , Femenino , Humanos , Masculino , Persona de Mediana Edad , Curva ROC
10.
Sci Total Environ ; 607-608: 786-794, 2017 Dec 31.
Artículo en Inglés | MEDLINE | ID: mdl-28711008

RESUMEN

Water availability, resulting from either a lack of water or poor water quality is a key factor contributing to regional water stress. This study proposes a set of sector-wise characterization factors (CFs), namely consumptive and degradative water stresses, to assess the impact of water withdrawals with a life cycle assessment approach. These CFs consider water availability, water quality, and competition for water between domestic, agricultural and industrial sectors and ecosystem at the watershed level. CFs were applied to a case study of regional water management of industrial water withdrawals in Taiwan to show that both regional or seasonal decrease in water availability contributes to a high consumptive water stress, whereas water scarcity due to degraded water quality not meeting sector standards has little influence on increased degradative water stress. Degradative water stress was observed more in the agricultural sector than in the industrial sector, which implies that the agriculture sector may have water quality concerns. Reducing water intensity and alleviating regional scale water stresses of watersheds are suggested as approaches to decrease the impact of both consumptive and degradative water use. The results from this study may enable a more detailed sector-wise analysis of water stress and influence water resource management policies.

11.
J Chem Phys ; 146(20): 203332, 2017 May 28.
Artículo en Inglés | MEDLINE | ID: mdl-28571331

RESUMEN

We measure the center-of-mass diffusion of poly(methyl methacrylate) (PMMA)-grafted nanoparticles (NPs) in unentangled to slightly entangled PMMA melts using Rutherford backscattering spectrometry. These grafted NPs diffuse ∼100 times slower than predicted by the Stokes-Einstein relation assuming a viscosity equal to bulk PMMA and a hydrodynamic NP size equal to the NP core diameter, 2Rcore = 4.3 nm. This slow NP diffusion is consistent with an increased effective NP size, 2Reff ≈ 20 nm, nominally independent of the range of grafting density and matrix molecular weights explored in this study. Comparing these experimental results to a modified Daoud-Cotton scaling estimate for the brush thickness as well as dynamic mean field simulations of polymer-grafted NPs in athermal polymer melts, we find that 2Reff is in quantitative agreement with the size of the NP core plus the extended grafted chains. Our results suggest that grafted polymer chains of moderate molecular weight and grafting density may alter the NP diffusion mechanism in polymer melts, primarily by increasing the NP effective size.

12.
Asia Pac J Public Health ; 29(3): 219-228, 2017 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-28434253

RESUMEN

This study aims at determining the level of depression and suicidal status of adult HIV test-seekers. Of the total enrolled 850 males, almost 50% reported some risk behaviors, 38.9% experienced depression, and 7.2% had suicidal ideation. Subjects with risky sexual behaviors in terms of repeated HIV test, had a history of sexually transmitted disease, engaged in one-night stands, or did not use condoms all the time with causal sexual partners were more likely to have depression. Furthermore, subjects who were bisexual/homosexual, engaged in Internet sex, engaged in one-night stands, or used addictive drugs within the past 6 months were more likely to experience suicidal ideation. The HIV testers are at risk of experiencing depression and suicidal ideation; each is associated with different types of risky sexual behaviors. It is essential for the health authority to further provide mental health services for HIV testers and to draw up an effective strategy in reducing unprotected sexual behaviors.


Asunto(s)
Depresión/epidemiología , Asunción de Riesgos , Conducta Sexual/psicología , Ideación Suicida , Adulto , Consejo , Infecciones por VIH/diagnóstico , Infecciones por VIH/psicología , Humanos , Masculino , Tamizaje Masivo , Aceptación de la Atención de Salud , Factores de Riesgo , Taiwán/epidemiología , Programas Voluntarios , Adulto Joven
13.
Kidney Int ; 89(3): 574-85, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26880454

RESUMEN

Patients with chronic kidney disease have an increased prevalence of peripheral arterial disease. Endothelial progenitor cells (EPC) are pivotal in neovascularization, but their role in mediating peripheral arterial disease in chronic kidney disease is not fully known. Here we studied the impact of indoxyl sulfate, a protein-bound uremic toxin, on EPC function in response to tissue ischemia or cell hypoxia in mice that underwent subtotal nephrectomy or sham operation. At 16 weeks, unilateral hindlimb ischemia was induced in all. Four weeks later, subtotal nephrectomy mice had significantly increased plasma levels of indoxyl sulfate, reduced reperfusion, decreased EPC mobilization, and impaired neovascularization in ischemic hindlimbs compared with control mice. Treatment with AST-120, an oral adsorbent of uremic toxins, reversed these changes. Ischemia-induced protein expression including phospho-eNOS, phospho-STAT3, interleukin-10, and VEGF were significantly decreased in ischemic hindlimbs of subtotal nephrectomy mice versus control mice; all effects were reversed by AST-120. Subtotal nephrectomy mice fed a diet with indole for 12 weeks resulted in impaired neovascularization in ischemic hindlimbs; also reversed by AST-120. In cultured human EPCs, VEGF expression was increased in hypoxia through HIF-1α and interleukin-10/STAT3 signaling; effects suppressed by pretreatment with indoxyl sulfate. Moreover, indoxyl sulfate markedly attenuated hypoxia-induced EPC migration and tube formation. Thus, indoxyl sulfate may be a therapeutic target for EPC-rescue of impaired neovascularization in patients with chronic kidney disease and peripheral arterial disease.


Asunto(s)
Movimiento Celular , Células Progenitoras Endoteliales/metabolismo , Indicán/sangre , Isquemia/sangre , Músculo Esquelético/irrigación sanguínea , Neovascularización Fisiológica , Uremia/sangre , Proteínas Angiogénicas/genética , Proteínas Angiogénicas/metabolismo , Animales , Trasplante de Médula Ósea , Carbono/farmacología , Movimiento Celular/efectos de los fármacos , Células Cultivadas , Modelos Animales de Enfermedad , Células Progenitoras Endoteliales/efectos de los fármacos , Células Progenitoras Endoteliales/patología , Regulación de la Expresión Génica , Miembro Posterior , Humanos , Mediadores de Inflamación/metabolismo , Isquemia/genética , Isquemia/patología , Isquemia/fisiopatología , Masculino , Ratones Endogámicos C57BL , Neovascularización Fisiológica/efectos de los fármacos , Nefrectomía , Óxidos/farmacología , Flujo Sanguíneo Regional , Transducción de Señal , Factores de Tiempo , Transfección , Regulación hacia Arriba , Uremia/tratamiento farmacológico
14.
Nat Commun ; 7: 10482, 2016 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-26805748

RESUMEN

Crystal-amorphous transformation achieved via the melt-quench pathway in phase-change memory involves fundamentally inefficient energy conversion events; and this translates to large switching current densities, responsible for chemical segregation and device degradation. Alternatively, introducing defects in the crystalline phase can engineer carrier localization effects enhancing carrier-lattice coupling; and this can efficiently extract work required to introduce bond distortions necessary for amorphization from input electrical energy. Here, by pre-inducing extended defects and thus carrier localization effects in crystalline GeTe via high-energy ion irradiation, we show tremendous improvement in amorphization current densities (0.13-0.6 MA cm(-2)) compared with the melt-quench strategy (∼50 MA cm(-2)). We show scaling behaviour and good reversibility on these devices, and explore several intermediate resistance states that are accessible during both amorphization and recrystallization pathways. Existence of multiple resistance states, along with ultralow-power switching and scaling capabilities, makes this approach promising in context of low-power memory and neuromorphic computation.

16.
ACS Appl Mater Interfaces ; 7(12): 6383-90, 2015 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-25781005

RESUMEN

A stacked oxide semiconductor of n-type ZnO/p-type NiO with diode behavior was proposed as the novel charge-trapping layer to enable low-voltage flash memory for green electronics. The memory performance outperforms that of other devices with high κ and a nanocrystal-based charge-trapping layer in terms of a large hysteresis memory window of 2.02 V with ±3 V program/erase voltage, a high operation speed of 1.88 V threshold voltage shift by erasing at -4 V for 1 ms, negligible memory window degradation up to 10(5) operation cycles, and 16.2% charge loss after 10 years of operation at 85 °C. The promising electrical characteristics can be explained by the negative conduction band offset with respect to Si of ZnO that is beneficial to electron injection and storage, the large number of trapping sites of NiO that act as other good storage media, and most importantly the built-in electric field between n-type ZnO and p-type NiO that provides a favorable electric field for program and erase operation. The process of diode-based flash memory is fully compatible with incumbent VLSI technology, and utilization of the built-in electric field ushers in a new avenue of accomplishing green flash memory.

17.
Nanoscale Res Lett ; 9(1): 275, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24936165

RESUMEN

A simplified one-diode one-resistor (1D1R) resistive switching memory cell that uses only four layers of TaN/ZrTiO x /Ni/n(+)-Si was proposed to suppress sneak current where TaN/ZrTiO x /Ni can be regarded as a resistive-switching random access memory (RRAM) device while Ni/n(+)-Si acts as an Schottky diode. This is the first RRAM cell structure that employs metal/semiconductor Schottky diode for current rectifying. The 1D1R cell exhibits bipolar switching behavior with SET/RESET voltage close to 1 V without requiring a forming process. More importantly, the cell shows tight resistance distribution for different states, significantly rectifying characteristics with forward/reverse current ratio higher than 10(3) and a resistance ratio larger than 10(3) between two states. Furthermore, the cell also displays desirable reliability performance in terms of long data retention time of up to 10(4) s and robust endurance of 10(5) cycles. Based on the promising characteristics, the four-layer 1D1R structure holds the great potential for next-generation nonvolatile memory technology.

18.
J Infect Dis ; 209(2): 224-35, 2014 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-23956440

RESUMEN

Skin and soft-tissue infections (SSTIs) caused by community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) have emerged as major health problems throughout the world. Most SSTI CA-MRSA strains produce Panton-Valentine leukocidin (PVL), but its contribution to CA-MRSA pathogenesis is poorly defined. Here, we used an endemic PVL-positive SSTI-causing CA-MRSA strain from Taiwan, together with an isogenic PVL-knockout mutant (Δpvl) and complemented PVL-positive derivative, to evaluate the role of PVL in the pathogenesis of CA-MRSA in the RHEK-1 human keratinocyte cell line and a rabbit skin infection model. We found that both PVL-positive CA-MRSA and isogenic Δpvl strains attached and were engulfed into endosomes of RHEK-1 cells within 1 hour following infection. However, by 2 hours after infection PVL-positive CA-MRSA more effectively disrupted endosomes, escaped into the cytoplasm, and replicated intracellularly. By 6 hours after infection, the PVL-positive strain caused significantly more caspase-dependent keratinocyte apoptosis than the isogenic Δpvl mutant. In the rabbit infection model, 1 week following infection the wild-type strain produced significantly more widespread lesions and cell apoptosis than the isogenic Δpvl mutant. These findings indicate that PVL is an important virulence factor that enables CA-MRSA to produce necrotizing skin infections by allowing the bacteria to escape from endosomes, replicate intracellularly, and induce apoptosis.


Asunto(s)
Apoptosis , Toxinas Bacterianas/metabolismo , Endosomas/microbiología , Exotoxinas/metabolismo , Queratinocitos/microbiología , Leucocidinas/metabolismo , Staphylococcus aureus Resistente a Meticilina/patogenicidad , Factores de Virulencia/metabolismo , Animales , Bacterias , Línea Celular , Infecciones Comunitarias Adquiridas/microbiología , Modelos Animales de Enfermedad , Femenino , Eliminación de Gen , Prueba de Complementación Genética , Humanos , Lagomorpha , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Conejos , Infecciones Cutáneas Estafilocócicas/microbiología , Taiwán , Virulencia
19.
J Phys Chem B ; 117(49): 15675-83, 2013 Dec 12.
Artículo en Inglés | MEDLINE | ID: mdl-23977966

RESUMEN

An analytic model for the slowing down of polymer chain diffusion in nanocomposites attributable to excluded volume effects is presented. The nanocomposite is modeled as an ensemble of cylinders through which the polymer chains diffuse. The reduction of polymer diffusion in each cylinder is equated with the reduction of diffusion for a sphere through a cylinder. The distribution of cylinder diameters within the ensemble is determined from statistical mechanical theories based on the packing of spherical particles. For low loadings of spherical particles in nanocomposites, this model results in a master curve for the reduced diffusion coefficient. With no adjustable parameters, the model agrees with recent data for tracer diffusion measurements in polymer nanocomposites at low loading.

20.
Crit Care Med ; 41(7): 1754-60, 2013 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-23685637

RESUMEN

OBJECTIVE: Enterovirus 71-induced brainstem encephalitis with pulmonary edema and/or neurogenic shock (stage 3B) is associated with rapid mortality in children. In a small pilot study, we found that milrinone reduced early mortality compared with historical controls. This prospective, randomized control trial was designed to provide more definitive evidence of the ability of milrinone to reduce the 1-week mortality of stage 3B enterovirus 71 infections. DESIGN: Prospective, unicenter, open-label, randomized, controlled study. SETTING: Inpatient ward of a large tertiary teaching hospital in Ho Chi Minh City, Vietnam. PATIENTS: Children (≤ 18 yr old) admitted with proven enterovirus 71-induced pulmonary edema and/or neurogenic shock. INTERVENTIONS: Patients were randomly assigned to receive intravenous milrinone (0.5 µg/kg/min) (n = 22) or conventional management (n = 19). Both groups received dopamine or dobutamine and intravenous immunoglobulin. MEASUREMENTS AND MAIN RESULTS: The primary endpoint was 1-week mortality. The secondary endpoints included length of ventilator dependence and hospital stay and adverse events. The median age was 2 years with a predominance of boys in both groups. The 1-week mortality was significantly lower, 18.2% (4/22) in the milrinone compared with 57.9% (11/19) in the conventional management group (relative risk = 0.314 [95% CI, 0.12-0.83], p = 0.01). The median duration of ventilator-free days was longer in the milrinone treatment group (p = 0.01). There was no apparent neurologic sequela in the survivors in either group, and no drug-related adverse events were documented. CONCLUSIONS: Milrinone significantly reduced the 1-week mortality of enterovirus 71-induced pulmonary edema and/or neurogenic shock without adverse effects. Further studies are needed to determine whether milrinone might be useful to prevent progression of earlier stages of brainstem encephalitis.


Asunto(s)
Cardiotónicos/uso terapéutico , Infecciones por Enterovirus/virología , Milrinona/uso terapéutico , Edema Pulmonar/tratamiento farmacológico , Choque/tratamiento farmacológico , Cardiotónicos/administración & dosificación , Preescolar , Dobutamina/uso terapéutico , Dopamina/uso terapéutico , Infecciones por Enterovirus/mortalidad , Femenino , Humanos , Inmunoglobulinas/uso terapéutico , Lactante , Infusiones Intravenosas , Tiempo de Internación , Masculino , Milrinona/administración & dosificación , Estudios Prospectivos , Edema Pulmonar/mortalidad , Edema Pulmonar/virología , Respiración Artificial , Choque/mortalidad , Choque/virología , Vietnam
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA